don't worry Kate, we've all been there. But now that you know how bad it feels when you fall outa the wagon, you're gonna be a hundred times stronger and more careful this time.
When I hang out with a gang of drinkers, the first thing I do is get a soft drink or something in a glass which looks similar to the one they are having booze in. And then I keep on drinkin (soft drink) while the party lasts...its been very effective for me, hope it helps you the next time on.
All the best